1. Chasmanthium latifolium (Michx.) H.O. Yates (river oats, inland sea oats, wild oats, broadleaf spike grass)

Pl. 119 a–i; Map 570

Uniola latifolia Michx.

Plants with stout rhizomes, forming loose colonies. Flowering stems 90–150 cm long, glabrous. Leaf blades 9–25 cm long, (5–)10–21 mm wide, glabrous or sparsely hairy near the base. Leaf sheaths glabrous. Inflorescences open panicles with the branches nodding or drooping at maturity (often ascending during development). Spikelets (15–)20–40 mm long, long‑stalked, ovate to elliptic in outline and appearing very flat at maturity, with 6–20 florets. Glumes 5–8 mm long, narrowly lanceolate, 5‑ or 7‑nerved. Lemmas 6–13 mm long, those of the sterile floret(s) similar to the glumes, those of the fertile florets narrowly oblong‑ovate, 11–15‑nerved. Stamens with the anther 0.5–4.0 mm long (0.5–0.9 in cleistogamous florets, longer in open‑flowering florets), yellow. Fruits 3–5 mm long, mostly hidden by the lemmas at maturity. 2n=48. July–October.

Common nearly throughout the state, but absent from northwesternmost Missouri and most of the Mississippi Lowlands Division (eastern U.S. west to Nebraska and Texas; Mexico). Bottomland forests, mesic upland forests in ravines and valleys, banks of streams and rivers, and bases of bluffs.

This attractive species has become popular as a shade‑tolerant ornamental in gardens. The dried inflorescences are used in flower arrangements.